Optical product detection sensor

A sensor, comprising:

• an emitter that directs light into a fluid delivery medium in which presence or absence of a product is to be determined;
• a first detector that generates a first detector output based on detection of light within a first wavelength range transmitted through the fluid delivery medium;
• a second detector that generates a second detector output based on detection of light within a second wavelength range transmitted through the fluid delivery medium;
• a controller that calculates a combination output based on the first and second detector outputs, calculates a color ratio, and determines presence or absence of the product within the fluid delivery medium based on a comparison of the first detector output with at least one first out-of-product threshold, a comparison of the second detector output with at least one second out-of-product threshold, a comparison of the combination output with at least one combined out-of-product threshold, and a comparison of the color ratio with a color ratio out-of-product threshold.

A method comprising:

• directing light into a fluid delivery medium in which presence or absence of a product is to be determined;
• generating a first detector output based on detected light within a first wavelength range transmitted through the fluid delivery medium;
• generating a second detector output based on to detected light within a second wavelength range transmitted through the fluid delivery medium;
• normalizing the first and second detector outputs based on baseline detector outputs obtained when product is present in the fluid delivery medium, thereby producing normalized first and second detector outputs;
• calculating a first combination output based on the normalized first and second detector outputs;
• calculating a second combination output based on the normalized first and second detector outputs;
• calculating a color ratio based on the first and second detector outputs;
• comparing the normalized first detector output with a first group of out-of-product thresholds;
• comparing the normalized second detector output with a second group of out-of-product thresholds;
• comparing the first combination output with a third group of out-of-product thresholds;
• comparing the second combination output with a fourth group of out-of-product thresholds;
• determining presence of product in the fluid delivery medium when none of the out-of-product thresholds of the first, second, third, and fourth groups of out-of-product thresholds are satisfied;
• if any of the out-of-product thresholds of the first, second, third, or fourth groups of out-of-product thresholds are satisfied, comparing the color ratio with a fifth group of out-of-product thresholds;
• and
• determining absence of product in the fluid delivery medium when none of the out-of-product thresholds of the fifth group of out-of-product thresholds are satisfied.